Tip for valve member and method of assembling same

ABSTRACT

The needle valve stem of a float-controlled valve is provided with a tip made of resilient material such as a fluoroelastomer. The end of the valve stem includes a cylindrical bore and the resilient tip has a cylindrical portion disposed in that bore which has a relaxed diameter greater than the diameter of the bore. The tip is inserted in the bore by stretching its cylindrical portion axially to reduce the diameter of the cylindrical portion. Once in the bore, the stretching force is released whereupon the tip tends to return to its relaxed state and in doing so creates an inherent bias which acts against the bore walls to hold the tip on the valve stem. The tip includes an annular, convex in transverse cross section projection which engages an unobstructed surface surrounding the valve orifice through which flow occurs. The tip closes the orifice to flow and does so without protruding into the orifice.

United States Patent [72] Inventor William A. Biermann Brooktield, Wis.[21] Appl. No. 876,532 [22] Filed Nov. 13, 1969 [45] Patented Dec. 7,1971 [73] Assignee Controls Company of America Melrose Park, Ill.

[54] TIP FOR VALVE MEMBER AND METHOD OF ASSEMBLING SAME 6 Claims, 4Drawing Figs.

[52] U.S. Cl 137/434, 251/357 [5]] 1nt.C1 Fl6k 31/26 [50] Field olSearch 137/409, 410, 315, 434; 25 1/333, 334, 356, 357, 358; 29/157.1,156.7 A, 450

[56] References Cited UNITED STATES PATENTS 2,558,589 6/1951 Skolfield29/450 X 2,654,560 10/1953 251/357 X 2,687,277 8/1954 251/357 X2,693,929 11/1954 251/357X 3,213,524 10/1965 Pratheretal. 3,381,3515/1968 Szwargulski ABSTRACT: The needle valve stem of a float-controlledvalve is provided with a tip made of resilient material such as afluoroelastomer. The end of the valve stem includes a cylindrical boreand the resilient tip has a cylindrical portion disposed in that borewhich has a relaxed diameter greater than the diameter of the bore. Thetip is inserted in the bore by stretching its cylindrical portionaxially to reduce the diameter of the cylindrical portion. Once in thebore, the stretching force is released whereupon the tip tends to returnit its relaxed state and in doing so creates an inherent bias which actsagainst the bore walls to hold the tip on the valve stem. The tipincludes an annular, convex in transverse cross section projection whichengages an unobstructed surface surrounding the valve orifice throughwhich flow occurs. The tip closes the orifice to flow and does sowithout protruding into the ori- ,PATENIEMEB 71971 3625245 Jm errtorBACKGROUND OF INVENTION This invention relates to valves and toresilient tips for movable valve members and, more particularly, to theconnection of the tip to the valve stem, the manner of making thatconnection, and the closure of the. fixed orifice to flow by theresilient tip.

Resilient tips have been used in valves to achieve valve closure.Various types of connections have been proposed for mounting the tips onthe valve stem, these have generally taken the form of bonding,mechanical fasteners, mechanical interlocks, etc. For the most partthese methods of attachment have not been entirely satisfactory for anumber of reasons among which are that they have been relativelydifficult to assemble, complex in construction, and not completelyreliable.

This invention is concerned with providing a resilient tip on a movablevalve member and connecting that tip to the valve member.

SUMMARY OF INVENTION Among the general objects of this invention are toprovide an improved and simplified connection of a resilient tip on amovable valve member and one which facilitates the assembly of the tipto the valve member; and, furthermore, to achieve an improved closure ofa valve orifice with the resilient tip.

For the achievement of these and other objects, this invention proposesan arrangement wherein a movable valve member is provided with a bore inthe end thereof. A resilient tip is supported in the bore. To connectthe tip to the movable valve member the bore is provided with opposedwall portions which are spaced a preselected distance apart. Theresilient tip includes a portion which projects outwardly from themovable valve member and a second portion adapted to extend into thebore of the movable valve member. When the resilient tip is relaxed, thesecond portion has a transverse dimension which is greater than thepreselected distance between the opposed bore wall portions. To assemblethe tip onto the movable valve member, the second portion of the tip isstretched so that it becomes elongated and its transverse dimension isreduced sufficiently for insertion into the bore. Once in the bore, thestretching force on the second portion of the tip is released and, dueto its resiliency, that portion tends to return to its relaxed position.This provides an inherent bias which maintains engagement between thetip and the opposed walls of the bore thereby securely holding the tipassembled on the movable valve member.

Preferably, the resilient tip also includes a bore extending into thesecond portion thereof. This bore facilitates stretching the secondportion of the tip and moreover, permits a suitable elongated tool to beinserted into the tip. The tip can be stretched on the tool and the toolprovides the instrument by which the tip is inserted in the valve memberbore.

Also it is preferred that the projecting portion of the tip is annularand also is convex in transverse cross section. The resilient tip ismovable to close a fixed orifice of the valve to flow through the valve.The fixed orifice is surrounded by an unobstructed surface and theannular portion of the tip engages the unobstructed surface. The movablevalve member has generally unobstructed movement toward the unobstructedsurface generally throughout the extent of the projecting portion of thetip. Throughout this movement of the movable valve member is a valveclosing or sealing direction, the annular projection does not protrudeinto the fixed orifice.

DESCRIPTION OF DRAWINGS FIG. 1 is a view of a float-controlled oil valvein which this invention is embodied;

FIG. 2 is an enlarged section view of a portion of an assembled valvestem and resilient tip together with the fixed orifice illustrating thecooperation between the tip and orifice to close the valve to flow;

FIG. 3 is an exploded view of the tip and a portion of the valve stemillustrating the relationship between the relaxed resilient tip and thebore of the valve stem; and

FIG. 4 illustrates a step in assembling the tip.

DESCRIPTION OF PREFERRED EMBODIMENT The invention is illustrated asembodied in a float-actuated oil flow control valve 10. However, theinvention is specifically concerned with the resilient tip used on thevalve stem and the manner of connecting that tip to the valve stem and,in its more specific aspects, to the manner in which closure of thevalve to flow is achieved. Accordingly, the invention has applicationbroadly to valves and is not necessarily limited to any particular typeof valve or valve usage.

In valve 10 flow occurs from inlet 14 through passage 12 into floatreservoir 16. The construction and arrangement of needle valve stem 18,float 20, and the connection between float 20 and the needle valve stemcan take any generally accepted form. The valve can also be providedwith a safety cutotf float 21 and a cutoff actuator 24. The constructionand arrangement illustrated is generally that disclosed and claimed inUS. Pat. No. 2,547,995 of William A. Biermann et al., entitled FluidFlow Control Mechanism" and assigned to the assignee of thisapplication. Reliance is placed on this patent for a more completedescription of the valve structure should such a description becomenecessary. As alluded to briefly above, the amount of flow through valveI0 is controlled by the valve element which control flow spicificallythrough passage I2 from inlet 14 to valve chamber 16. Needle valve stem18 opens and closes passage 12 by moving axially with respect to passagel2 to close fixed orifice 26 provided in that passage.

Particular reference will now be made to FIG. 2-4 for a description ofresilient tip 28 and its connection to valve stem 18. End 30 of thevalve stem is provided with a cylindrical bore 32. Tip 28 is engaged inthe bore and is held on the valve stem solely by the frictionalengagement between the tip and the bore walls.

More specifically, tip 28 includes a portion 34 which, when the tip isassembled on the valve stem, projects axially from the end of the valvestem and is the part of the tip which cooperates in closing orifice 26to flow. The tip also includes a cylindrical portion 36 which fits intobore 32. Tip 28 is made of a suitable resilient material, such as afluoroelastomer, so that the tip is deformable but will tend to returnto a normal relaxed state when the deforming force is released. Therelaxed state of the tip is illustrated in FIG. 3 and in this stateportion 36 has a diameter which is greater than the diameter of bore 32.The tip being resilient can be deformed, specifically it can bestretched along the axial extension of portion 36 to reduce the diameterof that extension for insertion into the valve stem bore. In thestretched condition the tip is inserted into the bore and released. Uponrelease the tip tends to return to its normal state. However, since thebore diameter is less than the relaxed diameter of portion 36, that tipportion cannot return fully to its relaxed state. Consequently, aninherent biasing force is provided urging the tip into engagement withthe bore walls to hold the tip on the valve stem.

With this arrangement it will be noted that opposed portions of thewalls of bore 32 define a transverse dimension (e.g., a diameter) andthis transverse dimension is less than a corresponding transversedimension (e.g., a diameter) of tip portion 36 in its relaxed state.Friction engagement is then provided between the tip and the bore wallsto securely hold the tip on the valve stem.

Preferably, tip 28 is provided with an interior bore 38. This bore willaccommodate a suitable tool such as rod 40 upon which the tip can bestretched in an axial direction to reduce the diameter of thecylindrical portion, this is illustrated by the full line of FIG. 4. Rod40 also facilitates insertion of the tip into bore 32 while the tip isin a stretched condition. That is, rod 40 is inserted into bore 38 andthe tip is stretched over the rod to reduce the diameter of tip portion36 to less than that of bore 32 whereupon the tip is inserted in bore32. Rod 40 is then removed releasing tip portion 36 and allowing it toexpand into engagement with the walls of bore 32 as described above.

This arrangement provides a simplified and effective manner of mountinga resilient tip onto a valve stem.

A further problem encountered in the use of resilient valve tips toclose an orifice is the problem of the tip protruding into the orifice,in this instance orifice 26. When such protrusion occurs, the sealingsurface of the tip is indented and after continued use the tipindentation may take a relatively permanent set. Any such set caneventually interfere with proper seal off at the orifice since there isno assurance that the tip will engage in the orifice in the same mannerupon each operation. To achieve effective seal off at orifice 26,portion 34 of tip 28 is generally annular and is provided with a convexouter surface, i.e., the annular tip portion has a convex configurationin transverse cross section as seen in FIGS. 2 and 3. Surface 42immediately surrounding orifice 26 is planar and unobstructed and it ison this surface thattip 28 makes sealing engagement. The valve stem ispositioned so that the annular projection 34 engages surface 42 but atareas spaced laterally from the walls of orifice 26. It will be notedthat the valve stem is capable of unobstructed movement toward orifice46 in pressing tip 28 into sealing engagement with surface 42. The valvestem and portion 34 of the valve tip are so constructed and arrangedthat through out this unobstructed sealing movement of the valve stemtoward surface 42, the valve tip remains laterally spaced from theorifice and does not protrude into the orifice. This arrangementprovides an effective seal at the orifice even through extended usageand does not require close tolerance to be held either in manufacturingor assembly of the valve elements.

I claim:

1. A flow control valve comprising, in combination,

a valve member including a fixed orifice through which flow occurs,

a movable valve member having an end,

a generally resilient tip carried on said end and movable with saidvalve member,

means for moving said valve member relative to said orifice to move saidtip selectively into and out of closing engagement with said orifice,

means defining a bore in said end of said movable valve member with saidbore having generally opposed wall portions defining a transversedimension,

said tip including a first portion projecting from said end and a secondportion having a transverse dimension and an extension generally normalto said transverse dimension thereof, said tip characterized by having anormal relaxed state wherein said transverse dimension thereof isgreater than said transverse dimension of said bore and said tip beingstretchable along its extension to reduce the tip transverse dimensionand tending to return to its normal relaxed state from said stretchedstate when released whereby stretching of said tip extension reducessaid transverse tip dimension for insertion in said bore and release ofsaid tip causes said tip to expand in the direction of its transversedimension to engage said wall portions,

means defining an interior bore in said resilient tip extending throughsaid first tip portion into said second tip portion,

and said second tip portion disposed in said movable valve member boreand having an extension dimension greater than its relaxed extensiondimension and a transverse dimension less than its relaxed transversedimension so that said tip securely engages said wall portions due tosaid second tip portions's tendency to return toward its normal state.

2. The valve of claim 1 wherein said first tip portion is generallyannular and has a convex transverse cross section, wherein sard fixedorifice rs surrounded by an unobstructed surface,

and wherein said first tip portion engages said unobstructed surfacearound said fixed orifice to close said orifice to flow and said movablemember has generally unobstructed movement toward said orificesubstantially throughout the extent of the projection of said first tipportion, the entire sealing engagement between said tip and saidunobstructed surface being spaced from said orifice so that the closureof said orifice is effected throughout said range of unobstructedmovement without said first tip portion protruding into said orifice.

3. The valve of claim 2 wherein said bore and second tip portions arecylindrical and said transverse dimensions are diameters.

4. The valve of claim 3 wherein said means for moving said valve membercomprises a float mechanism.

5. The valve of claim 1 wherein said bore and second tip portions arecylindrical and said transverse dimensions are diameters.

6. A flow control valve comprising, in combination,

a valve member including a fixed orifice through which flow occurs,

a movable valve member having an end,

a generally resilient tip carried on said end and movable with saidvalve member,

means for moving said valve member relative to said orifice to move saidtip selectively into and out of closing engagement with said orifice,

means defining a bore in said end of said movable valve member with saidbore having generally opposed wall portions defining a transversedimension,

said tip including a first portion projecting from said end and a secondportion having a transverse dimension and an extension generally normalto said transverse dimension thereof, said transverse dimension beinggenerally uniform along the extension of said tip and said tipcharacterized by having a normal relaxed state wherein said transversedimension thereof is greater than said transverse dimension of said boreand said tip being stretchable along its extension to reduce the tiptransverse dimension and tending to return to its normal relaxed statefrom said stretched state when released whereby stretching of said tipextension reduces said transverse tip dimension for insertion in saidbore and release of said tip causes said tip to expand in the directionof its transverse dimension to engage said wall portions along theentire extension of said tip in said movable valve member bore,

and said second tip portion disposed in said bore and having anextension dimension greater than its relaxed extension dimension and atransverse dimension less than its relaxed transverse dimension so thatsaid tip securely engages said wall portions due to said second tipportion's tendency to return toward its normal state and generally alongthe entire extension of said tip in said movable valve member bore.

i t i t

1. A flow control valve comprising, in combination, a valve memberincluding a fixed orifice through which floW occurs, a movable valvemember having an end, a generally resilient tip carried on said end andmovable with said valve member, means for moving said valve memberrelative to said orifice to move said tip selectively into and out ofclosing engagement with said orifice, means defining a bore in said endof said movable valve member with said bore having generally opposedwall portions defining a transverse dimension, said tip including afirst portion projecting from said end and a second portion having atransverse dimension and an extension generally normal to saidtransverse dimension thereof, said tip characterized by having a normalrelaxed state wherein said transverse dimension thereof is greater thansaid transverse dimension of said bore and said tip being stretchablealong its extension to reduce the tip transverse dimension and tendingto return to its normal relaxed state from said stretched state whenreleased whereby stretching of said tip extension reduces saidtransverse tip dimension for insertion in said bore and release of saidtip causes said tip to expand in the direction of its transversedimension to engage said wall portions, means defining an interior borein said resilient tip extending through said first tip portion into saidsecond tip portion, and said second tip portion disposed in said movablevalve member bore and having an extension dimension greater than itsrelaxed extension dimension and a transverse dimension less than itsrelaxed transverse dimension so that said tip securely engages said wallportions due to said second tip portions''s tendency to return towardits normal state.
 2. The valve of claim 1 wherein said first tip portionis generally annular and has a convex transverse cross section, whereinsaid fixed orifice is surrounded by an unobstructed surface, and whereinsaid first tip portion engages said unobstructed surface around saidfixed orifice to close said orifice to flow and said movable member hasgenerally unobstructed movement toward said orifice substantiallythroughout the extent of the projection of said first tip portion, theentire sealing engagement between said tip and said unobstructed surfacebeing spaced from said orifice so that the closure of said orifice iseffected throughout said range of unobstructed movement without saidfirst tip portion protruding into said orifice.
 3. The valve of claim 2wherein said bore and second tip portions are cylindrical and saidtransverse dimensions are diameters.
 4. The valve of claim 3 whereinsaid means for moving said valve member comprises a float mechanism. 5.The valve of claim 1 wherein said bore and second tip portions arecylindrical and said transverse dimensions are diameters.
 6. A flowcontrol valve comprising, in combination, a valve member including afixed orifice through which flow occurs, a movable valve member havingan end, a generally resilient tip carried on said end and movable withsaid valve member, means for moving said valve member relative to saidorifice to move said tip selectively into and out of closing engagementwith said orifice, means defining a bore in said end of said movablevalve member with said bore having generally opposed wall portionsdefining a transverse dimension, said tip including a first portionprojecting from said end and a second portion having a transversedimension and an extension generally normal to said transverse dimensionthereof, said transverse dimension being generally uniform along theextension of said tip and said tip characterized by having a normalrelaxed state wherein said transverse dimension thereof is greater thansaid transverse dimension of said bore and said tip being stretchablealong its extension to reduce the tip transverse dimension and tendingto return to its normal relaxed state from said stretched state whenreleased whereby stretching of said tip extension reduces saidtransverse tip dimensioN for insertion in said bore and release of saidtip causes said tip to expand in the direction of its transversedimension to engage said wall portions along the entire extension ofsaid tip in said movable valve member bore, and said second tip portiondisposed in said bore and having an extension dimension greater than itsrelaxed extension dimension and a transverse dimension less than itsrelaxed transverse dimension so that said tip securely engages said wallportions due to said second tip portion''s tendency to return toward itsnormal state and generally along the entire extension of said tip insaid movable valve member bore.